Heat recovery ventilator



FIG. 1 is a perspective view of our novel heat recovery ventilator showing the top, side and end thereof;

FIG. 2 is a view of the end at the left side of FIG. 3;

FIG. 3 is a view of the top;

FIG. 4 is a view of the far side of FIG. 1;

FIG. 5 is a view of the other end; and,

FIG. 6 is view of the other side. 

The ornamental design for a heat recovery ventilator, as shown. 